Valves for internal combustion engines



Patented Dec. 29, l93

UNITE A'rsNT OFFICE VALVES FOR INTERNAL COMBUSTION ENGINES Clarence George Bieber Sumpter, Huntington, International Nickel C and Walter Franklin W. Va., assignors to The ompany, Inc., New York,

N. Y., a corporation of Delaware No Drawing. Application October 12, 1950, Serial No. 189,894

4 Claims. (Cl. 75-171) The present invention relates to special heatresisting articles, such as valves, valve seats,

ducing conditions which detrimentally aii'ect the life or the valve alloy. By reducing conditions is meant an atmosphere which is reducing to lead oxide or other lead compounds contained in combusted fuels or internal combustion engines as exemplified by a combusted lead-containing atmosphere containing an excess or carbon monoxide or hydrogen in amounts reducing to lead oxide or other lead compounds. Certain siliconcontaining alloys have been used for valves but have been found only partially eiiective. While some or these silicon-containing alloys show fairly good corrosion resistance in oxidizing leadcontalning atmospheres, these silicon-containing alloys did not always stand up in reducing jected to nuctuating atmospheres of combusted lead-containing iuels in internal combustion engines involved the introduction of sodiumcooled, hollow head valves with the aim of improving valve life by preventing over-heating of valves while in service. Another attempt involved the use of the positive valve rotator to insure proper valve seating, to maintain efiiover-all resistance of valves to corrosion by fiuctuating atmospheres of combusted lead-containing fuels involved the hard facing of valves with containing, non-ferrous alloys of the cobalt chromium-tungsten type. While the foregoing attempts have been partially beneficial in protaining a novel combination or elements within critical ranges.

/ It is the OUJeCt oi" the present invention to provice an improved heat-treatable, silicon-contaming valve alloy which has resistance to creep, combined with resistance to corrosion, erosion, and pitting when used in internal combustion engines.

Another object of the invention is to provide an improved neat-treatable, silicon-containing The invention also contemplates providing a heat-treatable alloy for valves and valve parts in internal combustion engines with the purpose or improving periormance characteristics or internai COmKJUbMOIl engines and extendingvalve liIe.

It is the further object of the invention to provide a special heat-resisting, si1icon-containing,

containing, nickel-base alloy provided by the present invention.

Other objects and advantages will become apparent from the following description.

Generally speaking, the present invention provides valve parts for internal combustion engines comprised of a heat-treatable, silicon-contain ing, nickel-chromium alloy containing critical amounts of titanium, silicon, manganese, and iron. The valve parts made at least in part of the present heat-treatable alloys, when exposed to the corrosive action of fluctuating atmospheres of lead-containing gases at elevated temperatures, i. e., gaseous combustion products of leaded fuels such as commonly prevail in internal combustion engines, exhibit an improved combination of chemical and physical properties, such as resistance to corrosion, erosion, and pitting, combined with excellent creep resistance and excellent strength and toughness at elevated temperatures, which combination of properties heretofore was not exhibited by valve parts made of prior art alloys.

More particularly, the present invention provides a valve part for internal combustion engines, e. g., a valve, comprised of a heat-treatable, silicon-containing, nickel-base alloy in which the silicon content is critically controlled in the copresence of titanium, manganese, and iron. The broad composition range of the heat-treatable, nickel-base alloy which has been found to give the results desired when employed as a valve alloy comprises about 15% to 17% chromium, up to about 8% iron, about 0.05% to 2.5% manganese, about 2.75% to 3.35% titanium, upto about 0.15% silicon, and the balance substantially all nickel. in employing the foregoing alloy in valve and valve parts of internal combustion engines, it is preferred that the manganese content should not be less than 1.75%. In addition, the alloy is preferably made substantially devoid of aluminum and carbon, although up to about 0.10% aluminum and up to about 0.10% carbon may be tolerated in the alloy without deleteriously affecting the alloy. The alloy may also contain small amounts of the incidental elements, such as copper, etc. Impurities, such as sulfur, lead, selenium, tellurium, bismuth, etc., arekept as low as is commercially practicable.

In carrying the invention into practice, it is preferred to have the valve alloy contain about 15% to 17% chromium, about 3% to 8% iron, about 2% to 2.5% manganese, about 2.85% to 3.35% titanium, about 0.005% to 0.10% silicon,

and the balance substantially all nickel. As

nickel usually contains a small amount of cobalt in association therewith, it"is understood that the term nickel as employed herein includes cobalt in incidental amounts, e. g., up to about 1%.

Titanium, which is essential as an age hardening strengthener, is maintained at least as high as about 2.75% and is preferably held at about- 2.85% or higher in applications involving structural components of heavy-dutyinternal com-'- bustion engines in which high physical strength and high hot hardness are important. Under conditions where optimum age hardening effect of titanium is desired, the carbon content of the alloy is kept as low as is commercially practicable and preferably does not exceed 0.08% maximum. As stated hereinbefore, the alloy is substantially devoid of aluminum which does not exceed about 0.10% of the alloy composition.

In testing alloys for their valve properties, hot hardness and the lead oxide corrosion, laboratory tests are often employed. The lead oxide test, which is used to confirm good properties of valve alloys, i. e., resistance of valve alloys to corrosion by lead-containing compounds, comprises testing a sample of the alloy in contact with molten lead oxide for a given length of time at a temperature of about 1650 F. under reducing conditions. While oxidizing conditions have been heretofore employed to test valve alloys in molten lead oxidathe resistance of valve alloys to lead oxide corrosion under oxidizing conditions is not the only criterion. Thus, alloys which showed excellent resistance to corrosion. under oxidizingconditions were not always satisfactory and in many instances were bad when employed as valves.

Several examples of alloys within the scope of the invention were tested for corrosion resistance in molten lead oxide and were found to have good properties. In testing these alloys, the specimens were solution treated for twohours at 2000 F. and then subjected to the destructive action of molten lead oxide for agiven length of time at a i 1 temperature of about1650 F. in a reducing com.-

busted natural gas atmosphere containing about 6%.carbon monoxide. Two alloys, which showed excellent valve properties when subjected to the lead oxide test, are given in Table I as follows:

Alloy No. 1 and alloy No. 2 gave excellent results on-the weight loss basis insofar as-overall corrosion was concernedwhen exposed to the corrosive action of molten lead oxide in the aforementionedtest. Alloy No. 1 and alloy No.- 2 also showed a greatly reduced tendency to pitting corrosion.

A series of alloys within the'scope of the invention, which were also tested in molten lead oxide under. reducing conditions in accordance with the foregoingtest. procedure, are given in Table II...

Table 11 'T 1 M Per ,Perw Per- Pcr- Pcr- Per- Per- Per- Alloy No. cent cent ce t c nt ccut cent (so the Ni Cl Ti re 51 Mn 0 in 1 15.90 2. 74 2.87 0.13. 0. "0. 15.32 2.88 0.2 1 one 0.49 0.01 0.022 15.07' 2.77 0.62 0.13 2.04 0. 0i 0. 044 15.38 I 2.00 0.52 0. 15 2. 29 0.03 0.023 15.36 .99 0.36 0.14 2.17 0.02 0.017 15.35 2. 04' 6. 32 0.13 2.19 0.02 0. 010 15.30 2.86 0.33 OQ05 2.18. 0.02 i 0. 014 15.35 2.75 6. 36 0.11 2.33 0.03 I 0.017 1 internal combustion-engines under. severeoperating conditions and which resist the corrosive action of combusted lead-containing atmospheres under both oxidizing and reducing conditions.

For the purpose of giving those skilled in the art a better appreciation of the present invention, a series of comparative tests were conducted with alloys having compositions outside the scope of the invention. These alloys were similarly exposed to the corrosive action of lead oxide at a temperature of about 1650 F. in a reducing, combusted, natural-gas atmosphere as hereinbefore described. For convenience, the alloys having compositions outside the scope of the present invention are listed in the following Table III.

Table III Per- Per- Per- Per- Per- Pcr- Per- Per- Percent ce t cent cent cent cent cent cent cent h i 'li I Fe Si Mn All of the alloys listed in Table III were unsatisfactory and failed under the aforementioned lead oxide test. Alloys E to J exhibited particularly poor properties as evidenced by very bad overall corrosion and very bad pitting.

The new and improved results provided by the present invention are obtained by subjecting the novel alloys to an appropriate age-hardening heat treatment to impart thereto an age-hardened structure as is well known to those skilled in the art. The heat treatment can comprise a high temperature solution treatment at a temperature within the range of about 1900 F. to about 2100 F'., followed by rapid cooling to below about 1500" F. in order to maintain most of the precipitable phases in solid solution, and by a subsequent aging treatment in the temperature range of about 1250 F. to about 1350 F. A preferred age-hardening heat treatment comprises heating at a temperature between about 1960 F. and about 2000 F., rapidly cooling to below about 1300 F. and then aging for about 16 to about 20 hours at about 1300 F. In employing an agehardening heat treatment on articles made of the alloy, e. g., valves, valve parts, etc., the solution treatment may be conducted as part of the hot working operation and, furthermore, it is not always necessary to use the high temperature so lution treatment. Where it is desired to modify the combination of properties, e. g., at elevated operating temperatures, the foregoing heat treatments can be'varied. Thus, a treatment above the aging temperature can be employed prior to the aforementioned aging treatment to modify the combination of properties at elevated temperatures. Such an intermediate treatment can be conducted within the range of about 1400 F. to 1750 F., e. g., at about 1400 F., or 1450" F., or 1590" FL, or 1550 F., or 1600 F'., or 1650 F.

By employing the novel combination of elements within the composition range contemplated by the present invention and heat treating in accordance with the foregoing, the valve alloys provided by the present invention possess high temperature physical and chemical properties markedly superior to those possessed by conventional valve alloys.

In the heat-treated condition, the novel alloys are particularly suitable for use as valves, valve parts, and other structural elements of internal combustion engines, including gas turbines and jet engines. These structural elements can be made entirely of the alloy or partly of the alloy. Thus, the structural elements can be cladded with the alloy.

The present invention is particularly applicable to parts for heavy-duty, internal combustion engines, e. g., valves, valve parts, and other structural elements, and especially applicable for service under extremely corrosive conditions, such as those involving reducing atmospheres as well as oxidizing and neutral atmospheres resulting from the combustion of leaded fuels.

It is to be observed that the present invention provides as an article of manufacture a heat-resistant internal combustion engine valve or valve part having resistance to the destructive action of combusted leaded fuels and comprising an agehardened, silicon-containing, nickel-base alloy.

Furthermore, the present invention provides a structural element which in normal use is subjected to the destructive action of combusted lead-containing fuels at elevated temperatures in internal combustion engines.

Moreover, the present invention provides a heat-resisting alloy having substantial resistance to the destructive action of corrosive leadatmospheres at elevated temperatures and particularly suitable for valves, valve parts, and other structural elements of internal combustion engines, including gas turbines and jet engines.

Although the present invention has been described in conjunction with preferred embodiis to be understood that modifications and variations may be resorted to without deconsidered to be within the purview and scope of the invention and appended claims.

We claim:

under oxidizing, neutral and reducing conditions, said hollow-headed valve being age-hardened, silicon-containing, nickel-base alloy DOSSGSSIOD. corrosion resistance to the lead oxide test and consisting essentially of about 15% to 17% chromium, about 2.85% to 3.35% titanium, about 2% to 215% manganese, about 0.005% to 0.10% silicon, up to about 0.08% carbon, about 3% to 8% iron, and the balance essentially nickel, said alloy being devoid of aluminum.

2. An internal combustion engine valve subjected in use at elevated temperatures to the destructive action of fluctuating atmospheres of under oxidizing, neutral and reducing conditions and containing a corrosive material taken from the group consisting of lead, lead oxide, lead sulfide, lead sulfate and lead bromide, said valve being comprised of an age-hardened, silicon-containing, nickel-base alloy possessing corrosion resistance to the lead oxide test and consisting essentially of about 15% to 17% chromium, about 2.75% to 3.35% titanium, about 1.75% to 2.5% manganese, silicon up to about 0.15%, up to about 0.10% carbon, iron up seen- 5354;

to about 8%, up to not more: than: 0 110% aluminum, and the balance nickel.

3. A heat-resisting internal combustion-engine valve part having substantial resistance atelevated temperatures to the destructive action of,

fluctuating, corrosive, lead-containing atmosplieres under oxidizing, neutral and reducing conditions, said heat-resisting Valve partbein'g comprised of an age-hardened alloy-possessing corrosion resistance to the lead oxidetest'and to 1.'7%-' consisting essentially of about 15% chromium, about 2.75% to 3.35% titanium, about 9.95% to 2.5% manganese, silicon up to about 0.15%, up to about 0.10% carbon, iron up to about 8%, and the balance nickel, said alloybeing substantially devoid of aluminum.

4. A" neat-resisting alloy suitable fol-internal I in 1 8 said heat resisting alloy possessing-corrosion re.- sistance to thelead oxidetest and consistingessentially of about-15% to 197% chromium, about 2.75% to 3.55% titanium, about 0.05% to 2.5% manganese, silicon up to about' 0.15 up' to about 0.10% carbon, iron up to about 8%, up to not more than 0.10% aluminum, and the balance nickel.

CLARENCE GEORGE BIEBER.

WALTER; FRANKLIN SUIVJIPTEEL.

References'Cited in the file of this patent umrnn STATES PATENTS Number Name Date 2,048,167 Pilling et a1. July 21, 1936 2,515,185 Bieber et a1 July 18, 1950 FOREIGN PATENTS Number Country Date 328,362 Great Britain .a May 8, 1930' 583,845 Great Britain Jan. 1, 1947 626,201; Great Britain July 12, 1949 

1. A HOLLOW-HEADED INTERNAL COMBUSTION ENGINE VALVE SUBJECTED IN USE AT ELEVATED TEMPERATURES TO THE DESTRUCTIVE ACTION OF FLUCTUATING ATMOSPHERES OF COMBUSTED LEAD-CONTAINING FUELS UNDER OXIDIZING, NEUTRAL AND REDUCING CONDITIONS, SAID HOLLOW-HEADED VALVE BEING COMPRISED OF AN AGE-HARDENED, SILICON-CONTAINING, NICKEL-BASE ALLOY POSSESSION CORROSION RESISTANCE TO THE LEAD OXIDE TEST AND CONSISTING ESSENTIALLY OF ABOUT 15% TO 17% CHROMIUM, ABOUT 2.85% TO 3.35% TITANIUM, ABOUT 2% TO 2.5% MANGANESE, ABOUT 0.005% TO 0.10% SILICON, UP TO ABOUT 0.08% CARBON, ABOUT 3% TO 8% IRON, AND THE BALANCE ESSENTIALLY NICKEL, SAID ALLOY BEING DEVOID OF ALUMINUM. 